Eco-friendly Synthesis of 3-(Aryl)-2,6-diphenylpyrimidin-4(3H)-ones, Ethyl-1-(aryl)-1,6-dihydro-2-(aryl)-6-oxopyrimidine-4-carboxylates and 6-(4-Arylphenyl)-2-isopropylpyrimidin-4(3H)-one